Information Security Stack Exchange is a question and answer site for information security professionals. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have seen articles advising that in order to make the most of an SSD, it should be connected in AHCI mode.

Some SSDs allow the ATA password to encrypt the encryption key so my question is this - does this ATA password work in AHCI mode? I have a feeling it doesn't.. in which case, is there an alternative?

I only have an i3 so want to avoid software encryption.


share|improve this question
Depending on your i3 version, it might support AES-NI, in which case you will barely feel anything with software encryption – Lucas Kauffman Jan 28 '13 at 12:42
Even on an i3, AES is ridiculously lightweight. I run TrueCrypt system encryption on an old P4 box with no issues. – Polynomial Jan 28 '13 at 12:44
My i3 doesn't support AES-NI, which is something I overlooked when I bought the laptop. There is a very noticeable slowdown with ubuntu home drive encryption enabled which alone is the reason I am considering buying an SSD with built in encryption. As a side note, is there a reason why TrueCrypt might be better performance-wise? – Mark Jan 28 '13 at 19:13

The disk lock is a built-in security feature in the disk. It is part of the ATA specification, and thus not specific to any brand or device. The disk lock can be enabled and disabled by sending special ATA commands to the drive. If a disk is locked, it will refuse all access until it is unlocked. Source

Based on that I believe that it is not part of the AHCI/SATA standard, however as other comments have suggested, Full disk encryption using software like true-crypt is recommended.


While the ATA disk lock is intended to be impossible to defeat without a valid password, there are workarounds to unlock a drive. Many data recovery companies offer unlocking services,[25] so while the disk lock will deter a casual attacker, it is not secure against a qualified adversary. The drive is simply 'locked' whereas TrueCrypt actually encrypts the data on the drive.

In addition, You should be aware that ATA mode has noticeable performance loss over AHCI. There are a number of comparisons available online between the performance benchmarks of the two. It might be that any performance impact on your system from FDE may be negated by using AHCI mode. You will need to test for your own system.

Hope that helps,

share|improve this answer
This is what I thought.. a question then.. why would SSD manufacturers offer ATA password encryption of the encryption key when they recommend that AHCI is used instead of ATA? Is there an equivalent? – Mark Jan 29 '13 at 12:04

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.